The document outlines the sources of international law as defined by the International Court of Justice, including treaties, customs, general principles of law, judicial decisions, and writings of publicists. It highlights the importance of treaties as a primary source, distinguishing between lawmaking treaties and treaty contracts, and discusses customs as an original source of law based on state practices. Additionally, it emphasizes the role of general principles and judicial decisions, noting that while decisions are subsidiary sources, writings from legal scholars contribute significantly to international law.